Harken's 57mm Fiddle Ratchet Block Swivel with Becket, Part No. 2674, has a sheave diameter of 57mm (2 1/4 inches) and can handle line diameters up to 10mm (3/8 inches). With a maximum working load of 359kg (792lbs), these Carbo Ratchets provide sailors with the perfect balance between holding power and controlled easing, allowing them to effortlessly hold onto loaded lines.